diff --git a/modules/swagger-codegen/src/main/java/io/swagger/codegen/DefaultCodegen.java b/modules/swagger-codegen/src/main/java/io/swagger/codegen/DefaultCodegen.java
index 3696fb1ca35..e3e5ab85e1b 100644
--- a/modules/swagger-codegen/src/main/java/io/swagger/codegen/DefaultCodegen.java
+++ b/modules/swagger-codegen/src/main/java/io/swagger/codegen/DefaultCodegen.java
@@ -3143,6 +3143,7 @@ public void addOperationToGroup(String tag, String resourcePath, Operation opera
             if(uniqueName.equals(op.operationId)) {
                 uniqueName = co.operationId + "_" + counter;
                 counter ++;
+                throw new RuntimeException("it's dangerous to overload \"" + op.nickname + "\",  with path " + op.path);
             }
         }
         if(!co.operationId.equals(uniqueName)) {
@@ -3956,6 +3957,7 @@ public void setIgnoreFilePathOverride(final String ignoreFileOverride) {
 
     public boolean convertPropertyToBoolean(String propertyKey) {
         boolean booleanValue = false;
+
         if (additionalProperties.containsKey(propertyKey)) {
             booleanValue = Boolean.valueOf(additionalProperties.get(propertyKey).toString());
         }
diff --git a/modules/swagger-codegen/src/main/java/io/swagger/codegen/DefaultGenerator.java b/modules/swagger-codegen/src/main/java/io/swagger/codegen/DefaultGenerator.java
index ccb51ddc207..258a50b8e62 100644
--- a/modules/swagger-codegen/src/main/java/io/swagger/codegen/DefaultGenerator.java
+++ b/modules/swagger-codegen/src/main/java/io/swagger/codegen/DefaultGenerator.java
@@ -985,6 +985,7 @@ protected Map<String, Object> processOperations(CodegenConfig config, String tag
             if (opIds.contains(opId)) {
                 counter++;
                 op.nickname += "_" + counter;
+                throw new RuntimeException("it's dangerous to overload \"" + op.nickname + "\",  with path " + op.path);
             }
             opIds.add(opId);
         }